TDIGEST.REVRANK
Syntax
TDIGEST.REVRANK key value [value ...]
- Available in:
- Redis Stack / Bloom 2.4.0
- Time complexity:
- O(N) where N is the number of values specified.
Returns, for each input value (floating-point), the estimated reverse rank of the value (the number of observations in the sketch that are larger than the value + half the number of observations that are equal to the value).
Multiple reverse ranks can be retrieved in a single call.
Required arguments
key
is key name for an existing t-digest sketch.
value
is input value for which the reverse rank should be estimated.
Return value
Array reply - an array of integers populated with revrank_1, revrank_2, ..., revrank_V:
- -1 - when
valueis larger than the value of the largest observation. - The number of observations - when
valueis smaller than the value of the smallest observation. - Otherwise: an estimation of the number of (observations larger than
value+ half the observations equal tovalue).
0 is the reverse rank of the value of the largest observation.
n-1 is the reverse rank of the value of the smallest observation; n denotes the number of observations added to the sketch.
All values are -2 if the sketch is empty.
Examples
redis> TDIGEST.CREATE s COMPRESSION 1000
OK
redis> TDIGEST.ADD s 10 20 30 40 50 60
OK
redis> TDIGEST.RANK s 0 10 20 30 40 50 60 70
1) (integer) -1
2) (integer) 0
3) (integer) 1
4) (integer) 2
5) (integer) 3
6) (integer) 4
7) (integer) 5
8) (integer) 6
redis> TDIGEST.REVRANK s 0 10 20 30 40 50 60 70
1) (integer) 6
2) (integer) 5
3) (integer) 4
4) (integer) 3
5) (integer) 2
6) (integer) 1
7) (integer) 0
8) (integer) -1redis> TDIGEST.CREATE s COMPRESSION 1000
OK
redis> TDIGEST.ADD s 10 10 10 10 20 20
OK
redis> TDIGEST.RANK s 10 20
1) (integer) 2
2) (integer) 5
redis> TDIGEST.REVRANK s 10 20
1) (integer) 4
2) (integer) 1